I'm not sure if there are any hard set rules for model construction. One ebjective is to get the best shape with the fewest poly count. What Darkedge mentioned about scaling is the closet to a rule. with Poser's size being very small the 10:1 ratio is what you have to get used to. This may not be much help but it's the only thing I've seen mentioned regardless of modelling app used.

I must remember to remember what it was I had to remember.